1. The present invention relates to a reflection type on-vehicle display where an analog meter is oriented downwardly within a meter hood and a display image of the meter is reflected by a reflector into the driver's eyes so that the driver sees a virtual image behind the reflector.
2. Prior Art
Conventional on-vehicle displays are mounted on the instrument panel of the vehicle to indicate various vehicle conditions to the driver. Such displays are designed so that the driver directly looks at a display image of the display. The driver sees scenes outside of the vehicle through the front windshield while driving. When he needs to know vehicle information such as speed, the driver has to substantially move his eyes to look at the display. It is difficult for the driver to quickly focus his eyes on the display close to his eyes after looking at a far way scene through the windshield, and vice versa. This is particularly inconvenient when the vehicle is running at a relatively high speed.
To overcome the aforementioned drawbacks, a reflection type on-vehicle display has been proposed where the display image is reflected by a reflector into the driver's eyes so that the driver sees the virtual image of the display at a long imaginary distance behind the reflector. Such a reflection type on-vehicle display allows the driver to look at the display without having to move his eyes through a large angle. FIG. 6 shows one such type of on-vehicle display. In the figure, a display or meter 51 is placed in position within a meter hood 50 and is oriented downwardly. Behind the display 51 is positioned a reflector 52 which reflects the image of the display 51 into the driver's eyes so that the driver sees a virtual image X behind the reflector 52.
Conventionally, the above-mentioned display 51 takes the form of a digital display. Digital displays are usually expensive compared with analog type displays, necessitating higher overall costs of on-vehicle display apparatus. Besides, some users prefer analog type meters to digital type meters. An analog type meter is designed so that a movement causes a pointer to rotate over the dial to indicate information on the vehicle. Many of the movements are of a cross coil type having a pair of coils which generate magnetic fields crossing each other. A current flows through each of the coils in accordance with a physical quantity to be measured, driving a magnet rotator into rotation in a direction of a resultant magnetic field produced by the pair of coils. The pointer moves with the magnet rotator to indicate the information on the vehicle.
FIG. 7 shows one such cross coil type movement. A movement 41 is provided with a cylindrical case 42 with its bottom closed. The case 42 has a coil bobbin 43 including an upper bobbin 43a and a lower bobbin 43b. Two coils 44 and 44 are wound around the coil bobbin 43 so that coils 44 and 44 cross each other. A magnet rotator 45 having magnetic poles S and N is positioned within the coil bobbin 43, rotating shaft 46 extends through the center of the magnet rotator 45 in line with the longitudinal axis of the coil bobbin 43. The coil bobbin 43 has a space for housing the magnet rotator 45. The space is formed with a recess in a bottom thereof as a bearing 47 at the center of the bottom of the space. The bearing 47 is filled with silicone oil.
The bearing 47 rotatably supports the shaft 46 while at the same time the silicone oil applies a damping force to the shaft 46 so that the pointer will not vibrate while the vehicle is running or will not oscillate about the shaft 46 before it properly indicates information on the vehicle. The magnet rotator 45 and the shaft 46 are free to rotate in all angles when the coils are not energized, and are driven to rotate through an appropriate angle when the coils are energized. A dial 48 is mounted above the movement 41 as shown in FIG. 8. A pointer 49 is fixed to the end portion of the shaft 46 projecting outwardly of the dial 48.
When an analog meter 40 is mounted as shown in FIG. 8 in place of the digital meter 51 in FIG. 6, the silicone oil may leak from the bearing 47 since the movement 41 is oriented downwardly. In addition, a certain mechanism is required to support the shaft 46 of the movement 41.